This is a USB power cord that powers up the Wireless Flasher You See Alert Receiver Model A0211.

What the item does: The Wireless Flasher You See Receiver flashes of white light when the doorbell transmitter is activated and flashes an off-white light for the videophone transmitter. Each receiver features a user-selectable LED brightness of 0.5W, 1W, or 1.5W. The light mode can be set to continuous or flashing. And the light duration can be set to either 15 or 90 seconds.

The Wireless LED Flasher You See remote control system works up to 100 meters (328 feet). In addition, you can easily adjust the frequency code setting so that a neighbor's unit won't conflict with your system.